Here's why:
* Short vowel sounds are typically quick and sharp, and they are often found in words where the vowel is followed by one consonant.
* Long vowel sounds are typically drawn out and are often found in words where the vowel is followed by a consonant and a silent "e", or where the vowel is part of a vowel digraph.
In the word "credit," the "e" at the end is silent, and the "i" is followed by the consonant "t," creating the short vowel sound.